Mostly, yeah. Of course polyamides also produce some nitrogen compounds and PVC also produces HCl that you have to deal with, etc.
But generally, plastics are very complex long-chain carbohydrates. Burning them at low temperatures produces all kinds of partially combusted horrible byproducts, but properly incinerating them results in just water and CO2.
I visited an incineration plan once and they showed how the make really sure the temperature is over 900 degrees Celsius st all times so that plastics and biological toxins are properly destroyed.
They also make sure there is lots of air available to the combustion process and thats done in an interesting way. They draw it in via the waste storage bunker solving two issues at once - the stinky air from all the waste gets effectively burned and the bunker is kept as negative air pressure so the smell doesn't get out.
And of course all the exhaust gases pass via a sophisticated fikter plant.
Aren't we then shooting ourselves in the foot then by being scared of burning trash/plastic waste? As an interim before solving all plastic waste, it seems like a much better solution than just stacking plastic into giant dumps.
Perhaps burning trash would be the better solution. But it seems fairly unpopular with people in general, at least in the U.S. - you can imagine how easy it is to generate violent opposition to put a trash-burning facility in any place.
An acquaintance of mine from high school for some reason devoted much of his life to promoting trash burning technology. It seems like a good cause, but a futile one.